A science fiction mumbo jumbo which metamorphosises into a love story. On paper, the idea is too weird to warrant a good film, but it does deliver.
A dead man’s memory of the last eight minutes of his life is planted on another dead man so that he can revisit the train just before it blows up and find the person who planted the bomb. Sound preposterous, and it is preposterous.
The train blows up several times. The suspect is caught several times. The dead hero finds the woman of his dreams several time. It’s an endless circle, yet it comes with a satisfying payoff.
Writes Roger Ebert: "Now comes the human touch. As he returns again and again to those fateful eight minutes, Colter finds that he can remember his previous visits, even though for Christina and others on the train, they are of course happening for the first time. This is the "Groundhog Day" paradox: You remember your previous passages through the same span of time. Colter begins to care for Christina, as well he might, as anyone who loved Michelle Monaghan in "Trucker" (2008) will understand. As the conscious occupant of this borrowed body, he apparently possesses free will and need not duplicate exactly what the original memory donor did.
"This involves the possibility that he could relive the memories of a man's final eight minutes and act in such a way as to affect the outcome. If the man were to survive — whose memories would he have, his own or his visitor's? Don't go there. The Army's no doubt brilliant Dr. Rutledge (Jeffrey Wright) starts out to account for the experiment, but abandons his explanation, which is our loss. If you had a speech in this movie actually saying in so many words how this was possible, it would rival the findings of such great thinkers as Dr. Moreau, Dr. Jekyll and Dr. Frankenstein.
"No matter. The director and writer, Duncan Jones and Ben Ripley, hurtle ahead with the speed of their commuter train, which like the man on the Grecian urn always speeds forward and never gets anywhere. Colter's challenge increases in complexity. The city grows ever closer to destruction. Christina becomes more poignant. The scientists grow more desperate."